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Serena Williams and Dominika Cibulkova set up an Australian Open quarter-final clash, after respective gritty three-set wins.
Cibulkova ousted Victoria Azarenka from the year's first major, winning an entertaining contest on Rod Laver Arena.
The 11th seed came out all guns blazing early, and defied a comeback from the 2012 and 2013 champion to prevail 6-2 3-6 6-3 in two hours and 10 minutes under the centre-court roof at Melbourne Park.
Twenty-one first-set winners helped Cibulkova get on top early, before she finished with 44 for the match.
Cibulkova had won the first set the past four times she had played Azarenka, however, she had turned it into victory only once in that stretch.
The Slovakian not only won after claiming the first set against Azarenka but she also beat the Belarusian for the first time in seven hard-court meetings.
Top seed Williams fought back from a set down in consecutive matches, seeing off 24th seed Garbine Muguruza in their last-16 encounter.
After being pushed to three sets by Elina Svitolina on Saturday, Williams was once again under pressure before prevailing 2-6 6-3 6-2 in two hours.
Muguruza ultimately could not keep up her stellar serving performance, and a dip in her first-service percentage - combined with an improvement from Williams - in the third set helped the American get the decisive breaks late.
Williams finished with 41 winners to Muguruza's 29, while they both hit 35 unforced errors for the encounter.
Sister Venus also won through to the quarter-finals for the first time in five years thanks to a 6-3 2-6 6-1 victory over world number six Agnieszka Radwanska.
Seven-time grand slam champion Venus Williams – seeded 18th - had not made it past the third round at Melbourne Park in four previous attempts since losing her quarter-final match to Li Na in 2010.
But the 34-year-old, who had 43 winners to go with 36 unforced errors, ended that drought thanks to a three-set win against last year's semi-finalist after two hours and five minutes on Rod Laver Arena.
The win earned Venus an all-American showdown against teenager Madison Keys, who accounted for countrywoman Madison Brengle 6-2 6-4.